My pet peeve of the day: shoppers in front of me in the supermarket checkout line who don’t understand the basic concept behind the conveyor belt, and in particular the sensor at the front that makes it stop. At least once a week I end up behind a dour old lady who, for some reason, has a phobia of her groceries touching the metal strip at the end of the conveyor belt, and keeps inching them backward. At first it’s just enough to move them out of the line of sight of the sensor, but as it starts moving again, she keeps moving them further and further backward, until she’s desperately clutching her groceries as mine move inexorably forward. Then, without fail, she turns and glares at me, as if it was all part of my master plan to cut in front of her by shoving her things out of the way.